A3: keep a project's DATABASE_URL away from a PGLite brain

With a PGLite config, buildGbrainEnv returned the caller env unchanged, so
a project's .env DATABASE_URL (autoloaded by Bun) reached gbrain: a false
broken-db at best, gbrain talking to the app's own Postgres at worst.
Inherited DATABASE_URL and GBRAIN_DATABASE_URL are now blanked for PGLite
configs (GSTACK_RESPECT_ENV_DATABASE_URL=1 still keeps them), and every
gbrain child runs from gbrain's config dir instead of the user's project,
so it cannot reload the project's .env / .env.local.

The old test that pinned pass-through for an engine:pglite config is
migrated: pass-through now applies only to configs that name neither a
database_url nor PGLite.

Co-authored-by: maxpetrusenkoagent <max.petrusenko.agent@gmail.com>

lib/gbrain-exec.ts

@@ -35,11 +35,13 @@
 
 import { existsSync, readFileSync } from "fs";
 import { join } from "path";
-import { homedir } from "os";
+import { homedir, tmpdir } from "os";
 import { spawnSync, spawn, execFileSync, type SpawnSyncReturns, type ChildProcess, type SpawnOptions } from "child_process";
 
 interface GbrainConfig {
   database_url?: string;
+  engine?: string;
+  database_path?: string;
 }
 
 export interface BuildGbrainEnvOptions {
@@ -95,9 +97,15 @@ export function gbrainConfigDir(env: NodeJS.ProcessEnv = process.env): string {
  * unchanged when:
  *   - `GSTACK_RESPECT_ENV_DATABASE_URL=1` (intentional opt-out),
  *   - the config file is missing or unparseable,
- *   - the config has no `database_url`,
+ *   - the config has no `database_url` and is not a PGLite config,
  *   - the caller already set DATABASE_URL to the same value.
  *
+ * A PGLite config has no URL to seed, so an inherited DATABASE_URL /
+ * GBRAIN_DATABASE_URL (Bun autoloads a project's `.env`) would make gbrain
+ * connect to the app's own database instead of its file brain (#1917). Both
+ * are blanked, not deleted: gbrain treats an empty value as unset, and an
+ * existing (empty) variable is never refilled by a child's dotenv autoload.
+ *
  * GBRAIN_PREPARE is never set here (#1965): gbrain auto-disables prepared
  * statements on transaction-mode poolers itself, and forcing them on breaks
  * every write with "prepared statement does not exist". A caller-set
@@ -122,7 +130,13 @@ export function buildGbrainEnv(opts: BuildGbrainEnvOptions = {}): NodeJS.Process
   } catch {
     return out;
   }
-  if (!cfg.database_url) return out;
+  if (!cfg.database_url) {
+    if (cfg.engine === "pglite" || cfg.database_path) {
+      out.DATABASE_URL = "";
+      out.GBRAIN_DATABASE_URL = "";
+    }
+    return out;
+  }
 
   const hadCaller = baseEnv.DATABASE_URL !== undefined;
   const alreadyMatch = baseEnv.DATABASE_URL === cfg.database_url;
@@ -249,6 +263,19 @@ export function gbrainInvocation(args: string[]): { cmd: string; argv: string[];
     : { cmd: "gbrain", argv: args, shell: false };
 }
 
+/**
+ * Working directory for a gbrain child (#1917). gbrain (a Bun program) and
+ * its own config loader read `.env` / `.env.local` from the working
+ * directory, so a child started inside the user's project can pick the
+ * project's DATABASE_URL back up. Children run from gbrain's config
+ * directory (or the OS temp dir before init) unless the caller names a cwd.
+ */
+export function gbrainChildCwd(cwd?: string, env: NodeJS.ProcessEnv = process.env): string {
+  if (cwd) return cwd;
+  const dir = gbrainConfigDir(env);
+  return existsSync(dir) ? dir : tmpdir();
+}
+
 export interface SpawnGbrainOptions {
   /** Timeout in milliseconds. Defaults to 30s. */
   timeout?: number;
@@ -276,7 +303,7 @@ export function spawnGbrain(args: string[], opts: SpawnGbrainOptions = {}): Spaw
   return spawnSync(inv.cmd, inv.argv, {
     encoding: "utf-8",
     timeout: opts.timeout ?? 30_000,
-    cwd: opts.cwd,
+    cwd: gbrainChildCwd(opts.cwd, opts.baseEnv),
     stdio: opts.stdio || ["ignore", "pipe", "pipe"],
     env: buildGbrainEnv({ baseEnv: opts.baseEnv, announce: opts.announce }),
     shell: inv.shell, // #1731: gbrain is a .cmd shim on Windows (+#2471 quoting)
@@ -311,7 +338,7 @@ export function spawnGbrainAsync(
   const inv = gbrainInvocation(args);
   return spawn(inv.cmd, inv.argv, {
     stdio: opts.stdio || ["ignore", "pipe", "pipe"],
-    cwd: opts.cwd,
+    cwd: gbrainChildCwd(opts.cwd, opts.baseEnv),
     env: buildGbrainEnv({ baseEnv: opts.baseEnv, announce: false }),
     shell: inv.shell, // #1731: gbrain is a .cmd shim on Windows (+#2471 quoting)
   });
@@ -326,7 +353,7 @@ export function execGbrainText(args: string[], opts: SpawnGbrainOptions = {}): s
   return execFileSync(inv.cmd, inv.argv, {
     encoding: "utf-8",
     timeout: opts.timeout ?? 30_000,
-    cwd: opts.cwd,
+    cwd: gbrainChildCwd(opts.cwd, opts.baseEnv),
     stdio: opts.stdio || ["ignore", "pipe", "pipe"],
     env: buildGbrainEnv({ baseEnv: opts.baseEnv, announce: opts.announce }),
     shell: inv.shell, // #1731: gbrain is a .cmd shim on Windows (+#2471 quoting)

lib/gbrain-local-status.ts

@@ -48,7 +48,7 @@ import {
 import { atomicWriteSync } from "./fs-atomic";
 import { homedir } from "os";
 import { dirname, join } from "path";
-import { buildGbrainEnv, gbrainConfigDir, isExecTimeout, NEEDS_SHELL_ON_WINDOWS } from "./gbrain-exec";
+import { buildGbrainEnv, gbrainChildCwd, gbrainConfigDir, isExecTimeout, NEEDS_SHELL_ON_WINDOWS } from "./gbrain-exec";
 import { resolveStateRoot } from "./state-root";
 
 export type LocalEngineStatus =
@@ -458,6 +458,7 @@ function freshClassify(env?: NodeJS.ProcessEnv): LocalEngineStatus {
       timeout: probeTimeoutMs(env),
       stdio: ["ignore", "pipe", "pipe"],
       env: buildGbrainEnv({ baseEnv: env ?? process.env }),
+      cwd: gbrainChildCwd(undefined, env ?? process.env),
       shell: NEEDS_SHELL_ON_WINDOWS, // #1731: gbrain is a .cmd shim on Windows
     });
     return "ok";

lib/gbrain-sources.ts

@@ -12,7 +12,7 @@
 import { execFileSync, spawnSync } from "child_process";
 import { realpathSync } from "fs";
 import { withErrorContext } from "./gstack-memory-helpers";
-import { execGbrainJson, gbrainInvocation } from "./gbrain-exec";
+import { execGbrainJson, gbrainChildCwd, gbrainInvocation } from "./gbrain-exec";
 import {
   detectAutopilot,
   decideSourceRemove,
@@ -123,6 +123,7 @@ export function probeSource(id: string, env?: NodeJS.ProcessEnv): SourceState {
       timeout: 30_000,
       stdio: ["ignore", "pipe", "pipe"],
       env,
+      cwd: gbrainChildCwd(undefined, env),
       shell: inv.shell, // #1731: gbrain is a .cmd shim on Windows (+#2471 quoting)
     });
   } catch (err) {
@@ -230,6 +231,7 @@ export async function ensureSourceRegistered(
         encoding: "utf-8",
         timeout: 30_000,
         env,
+        cwd: gbrainChildCwd(undefined, env),
         shell: rmInv.shell, // #1731: gbrain is a .cmd shim on Windows (+#2471 quoting)
       });
       if (rm.status !== 0) {
@@ -246,6 +248,7 @@ export async function ensureSourceRegistered(
       encoding: "utf-8",
       timeout: 30_000,
       env,
+      cwd: gbrainChildCwd(undefined, env),
       shell: addInv.shell, // #1731: gbrain is a .cmd shim on Windows (+#2471 quoting)
     });
     if (add.status !== 0) {
@@ -273,6 +276,7 @@ export function sourcePageCount(id: string, env?: NodeJS.ProcessEnv): number | n
       timeout: 30_000,
       stdio: ["ignore", "pipe", "pipe"],
       env,
+      cwd: gbrainChildCwd(undefined, env),
       shell: inv.shell, // #1731: gbrain is a .cmd shim on Windows (+#2471 quoting)
     });
   } catch {